Exercise 3.8 Foil production In the production of a certain foil (film), the foil is controlled by measuring the thickness of the foil in a number of points distributed over the width of the foil. The production is considered stable if the mean of the difference between the maximum and minimum measurements does not exceed 0.35 mm. At a given day, the following random samples are observed for 10 foils: Foil 1 2 3 4 5 7 8 9. 10 Max. in mm (ymax) 2.62 2.71 Min. in mm (ymin) 2.14 2.39 Max-Min (D) 2.18 2.25 2.72 2.34 2.63 1.86 2.84 2.93 1.86 1.92 2.33 2.00 2.25 1.50 2.27 2.37 0.48 0.32 0.32 0.33 0.39 0.34 0.38 0.36 0.57 0.56 The following statistics may potentially be used Imax = 2.508, min = 2.103, Symax = 0.3373, symin = 0.2834, sp 0.09664. %3D a) What is a 95% confidence interval for the mean difference? b) How much evidence is there that the mean difference is different from 0.35? State the null hypothesis, t-statistic and p-value for this question.